A065386 Successive record values of the cototient function (A051953).

0, 1, 2, 4, 6, 8, 12, 16, 22, 24, 30, 32, 36, 44, 46, 48, 54, 60, 66, 70, 72, 78, 88, 90, 92, 94, 96, 110, 120, 132, 138, 140, 162, 176, 180, 184, 198, 210, 220, 250, 264, 270, 294, 324, 330, 342, 352, 360, 382, 396, 402, 426, 440, 486, 500, 514, 522, 528, 550, 588

Offset

1,3

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Example

a(8)=22 because for m = 1...29 the cototient values are all smaller than cototient(30)=22, where 30=A065385(8) and 22 is the 8th term in the sequence of such local records.

Mathematica

a=0; s=0; Do[s = n-EulerPhi[n]; If[s>a, a=s; Print[s]], {n, 1, 10000}]
(* Second program: *)
With[{s = Array[# - EulerPhi@ # &, 10^3]}, Union@ FoldList[Max, s]] (* Michael De Vlieger, Nov 03 2017 *)

Prog

(PARI) r=-1; for(n=1, 1000, d=n-eulerphi(n); if(r<d, r=d; print1(r, ", ")))
(PARI) { n=0; x=-1; for (m=1, 10^9, c=m - eulerphi(m); if (c > x, x=c; write("b065386.txt", n++, " ", c); if (n==1000, return)) ) } \\ Harry J. Smith, Oct 17 2009

Crossrefs

Cototient(A065385(n)).

A006093 gives similar records for the totient function. A002093, A002182, A015702, A005250 are analogous sequences for other functions.

a(n) = A051953(A065385(n)).

Cf. A051953, A065386, A000010.

Sequence in context: A138934 A008764 A228354 * A048951 A326504 A058629

Adjacent sequences: A065383 A065384 A065385 * A065387 A065388 A065389

Keyword

nonn

Author

Labos Elemer, Nov 05 2001

Status

approved